Ovulation (Lat. ovum – an egg), the yield of mature, able to fertilize an egg from an ovarian follicle into the abdominal cavity, phase of menstrual cycle (ovarian cycle). Ovulation in women of childbearing age are periodically (Every 21-35 days). The frequency of its regulated neurohumoral mechanisms, mainly gonadotropins of the anterior pituitary and ovarian follicular hormone. Ovulation contributes to the accumulation of follicular fluid and thinning of the ovarian tissue that is located on a pole sticking out of the follicle. Constant for each woman's ovulatory rhythm undergoes a change within 3 months after the abortion, within one year after birth, and after 40 years, when the body is preparing for pre-menopausal.

Stops ovulation with the onset of pregnancy, even after the menstrual function. Establishing the period of ovulation is important when choosing the most effective time for fertilization, artificial insemination and in vitro fertilization. Subjective signs of ovulation can be intermittent abdominal pain, objective – increased mucous discharge from the vagina and lower rectal (basal) temperature on the day of ovulation to increase it the next day, increased progesterone levels in blood plasma and other ovulatory failure is due to dysfunction of the hypothalamic-pituitary-ovarian system and can be caused by inflammation of the genitalia, adrenal hyperplasia, or thyroid disease, systemic diseases, tumors of the pituitary and hypothalamus, stressful situations. Lack of ovulation is of childbearing age (anovulation) occurs in violation of the menstrual rhythm type oligomenorrhea (menses lasting 1-2 days), amenorrhea, dysfunctional uterine bleeding. Anovulation is always a cause of infertility women.